In addition to conventionally used liquid fuels, the use of gaseous fuels such as natural gas or hydrogen has increased over the past few years. However, the known injectors for liquid fuels are only conditionally suitable for such gaseous fuels, since gaseous fuels have different energy densities and volumes than liquid fuels. To ensure that internal combustion engines operated in this manner do not consume excessive fuel, it is necessary to inject the most precise gas quantities possible in each injection. The injector must also provide sufficient tightness between the individual injection processes. One advantageous sealing material for injectors operated using gaseous fuel would be elastomer materials. However, one problem inherent in such elastomeric seals is their limited temperature resistance and their susceptibility to wear, which prevents their use especially in the direct injection of gaseous fuel into a combustion chamber, because the temperatures at the valve tip are too high. As an alternative, metal-to-metal seals having two metallic sealing partners are able to be used at very high temperatures and high mechanical stressing. These two sealing partners ensure sufficient tightness for liquid fuels even for very high numbers of switching cycles, but problems arise with gaseous fuels because of the high wear of the valve seat that occurs. This is attributable to the lack of hydraulic damping, which is present when liquid fuel is involved. In the case of gaseous fuels, however, the repeated impacts of a tappet or the like on the valve seat leads to increased wear and undesired noise.
It would therefore be desirable, especially for gaseous fuels, to have an injector featuring an adequate service life as well as tightness.